Freeze-fracture characterization of 'young' and 'old' human erythrocytes

While 'young' and 'old' erythrocytes separated by density show differences in various biochemical properties, the membrane ultrastructure as demonstrated by freeze-fracture remains unchanged. This implies that although superficial membrane components may be affected by aging, and whole segments of membrane may be lost, the structural relationship between integral protein and lipid in the remaining membrane is not altered.